In previous studies, heterocyclic amines (HCAs) have been identified as carcinogenic and a risk factor for human cancer. Therefore, the present study was designed to identify bioactive natural products capable of controlling the formation of HCAs during cooking. For this purpose we have evaluated the effect of Rosa rugosa tea extract (RTE) on the formation of HCAs in ground beef patties fried at 160 °C or 220 °C. RTE is rich in phenolic compounds and capable of inhibiting the formation of free radicals. The pyrido[3,4-b]indole (norharman) and 1-methyl-9H-pyrido[3,4-b]indole (harman) contents were significantly (p < 0.05) decreased in RTE-treated patties at 220 °C. 9H-3-Amino-1-methyl-5H-pyrido[4,3-b]indole acetate (Trp-P-2) and 3-amino-1,4-dimethyl-5H-pyrido-[4,3-b]indole acetate (Trp-P-1) were not detected at 160 °C and were statistically (p < 0.01) reduced at 220 °C compared to the control. RTE remarkably inhibited the formation of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) at 220 °C (p < 0.001) and at 160 °C (p < 0.05). 2-Amino-9H-pyrido[2,3-b]indole (AαC) and 2-amino-3-methyl-9H-pyrido[2,3-b]-indole (MeAαC) were only detected in the control group at 160 °C but were comparatively (p > 0.05) similar in the control and treated groups at 220 °C. 2-Amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), and 2-amino-3,4,8-trimethylimidazo[4,5-f]-quinoxaline (4,8-DiMeIQx) were not detected in any sample. Total HCAs were positively correlated with cooking loss. In the RTE-treated groups, 75% of the total HCAs were decreased at 160 °C and 46% at 220 °C, suggesting that RTE is effective at both temperatures and can be used during cooking at high temperatures to lessen the amount of HCAs formed.

The present research investigated the antioxidant effect of rape (Brassica campestris L.) bee pollen (RBP) on salami during processing. Eight flavonoids in RBP ethanol extract were quantified by high-performance liquid chromatography-mass spectrometry (HPLC-MS) analysis, and quercetin, rutin, and kaempferol were the major bioactive compounds. The RBP ethanol extract exhibited higher total antioxidant capacity than 6-hydroxy-2,5,7,8-tertramethylchromancarboxylic acid (trolox) at the same concentration. The salami with 0.05% RBP extract had higher catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) activities than that of the control throughout the processing time (p < 0.05). Significant decreases in peroxide value (POV) and thiobarbituric acid-reactive substances (TBARS) were obtained in the final salami product with 0.05% RBP ethanol extract or 1% RBP (p < 0.05). These results suggested that RBP could improve oxidative stability and had a good potential as a natural antioxidant for retarding lipid oxidation.

The present study was conducted to explore the impact of novel water–oil mixed frying and traditional oil frying methods on the soybean oil quality and formation of trans fatty acids (TFAs) and heterocyclic amines (HCAs) in fried duck breast and skin during 60 frying cycles. The acid value of the soybean oil was 2.10 mg/g using the traditional oil frying and 1.08 mg/g using water–oil mixed frying at the 60th frying cycle. The peroxide value of the water–oil mixed fried soybean oil was significantly lower than that of the traditional frying method. Water–oil mixed frying delayed the formation of TFAs in the soybean oil. The traditionally oil fried skin showed increased TFAs (9tC16:1) content from 0.17 to 0.22 mg/g (29.4% increase), while those of the water–oil mixed fried samples increased from 0.16 to 0.20 mg/g (25.00% increase) compared to control. Harman, Norharman and AαC were detected in all the fried samples and PhIP was observed after the 20th frying cycle, while MeAαC was formed only at the 60th frying cycle in traditional fried duck breast. Therefore, it is concluded that the water–oil mixed frying method is more suitable to improve the quality and safety of fried duck skin and breast meat.

To investigate the possible degradation of the intramuscular connective tissue (IMCT) with cathepsin L, isolated IMCTs were incubated with purified cathepsin L in vitro. Here, we prepared purified cathepsin L from bovine pancreas by using DEAE Sephacel, Sephacryl S-100 HR, SP Sepharose FF, and con A-Sepharose affinity chromatography in sequence. An SDS-PAGE analysis of CNBr-digested peptides showed that the degradation of collagen in IMCT could take place on terminal non-helical peptides rather than the triple helix region. Decorin (DCN) was clearly degraded at a pH of 5.0. The T_P and T_O of intramuscular connective tissue decreased to 41.41 °C and 43.79 °C, respectively. In the cathepsin L treatment of pH 5.0, the decreases in the T_P and T_O of IMCT were more sensitive than they were at pH 5.5~6.5.

Roasting meat involves simultaneous heat and mass transfer, colour and flavour development and the formation of hazardous chemicals. The objectives of this study were to evaluate the effects of temperature and time on colour, 3,4-benzo(a)pyrene (BaP) and heterocyclic aromatic amines (HCAs) in roast duck skin during forced hot-air drying at less than 130 °C. The results showed that surface and internal temperatures of duck carcasses increased with drying time, rising to 111.9 and 83.7 °C, respectively. The curves of water activity (a_w) and red index (a*) intersected at 50 min because of the decrease in a_w and the increase in a* on the skin with drying time. The drastic decline in a_w promoted colour development on the duck surface. BaP and carcinogenic HCAs were not detected in hot-air drying ducks, convincing us that the mild cooking method under forced hot-air drying could effectively reduce or eliminate the risk of certain human cancers.

Fluoride (F) is one of the major chemical substances that damage the renal tissue, resulting in an increase in the excretion of sodium (Na+) and chloride (Cl-), and enhancing creatinine (Cr), uric acid (UA), blood urea nitrogen (BUN), and potassium (K+) levels. Results revealed that on the 16th day in groups B, D, E, and G, Cr values were significantly (P<0.05) increased. On the 31st day in group F, the Cr value was significantly (P<0.05) decreased, whereas in groups B, D, E, and G, Cr values were significantly increased (P<0.05). On the 16th and 31st day, in yogurt-treated groups (C and F), UA values were significantly (P<0.05) decreased, whereas in groups B, D, E, and G, UA values were significantly (P<0.05) increased. On the 16th and 31st day, in groups B, D, E, and G, BUN levels were significantly (P<0.05) increased. On the 16th and 31st day, in groups B and E, Na+ levels were significantly (P<0.05) decreased, whereas in groups C, D, F, and G, Na+ levels were significantly (P<0.05) increased. Likewise, on the 16th and 31st day, in groups B, D, E, and G, K+ levels were significantly (P<0.05) increased. On the 16th day, in groups B and E, Cl- levels were significantly (P<0.05) decreased, while in groups F and G, Cl- levels were significantly (P<0.05) increased. On the 31st day, in groups B and E, Cl- levels were significantly (P<0.05) decreased, while in groups C, D, F, and G, Cl- levels were significantly (P<0.05) increased. It has been concluded that increased levels of Cr, UA, BUN, K+, and reduced levels of Na+ and Cl- were observed in all fluoride-treated groups. Yogurt-treated groups showed decreased levels of Cr, UA, BUN, and K+, and increased levels of Na+ and Cl- in experimental rabbits.